Cortnee Brantley, 22, had been accused of not telling authorities she knew Dontae Morris was a convicted felon who illegally had a loaded gun on the night officers David Curtis and Jeffrey Kocab were killed.

Brantley faced an obscure and rarely used federal charge: misprision of a felony.

To prove it, the government had to show she not only knew about the gun, but took some specific act to conceal that fact.

"I don't see an act of concealment anywhere," U.S. District Judge James S. Moody Jr. told attorneys.

Morris, 25, was a passenger in Brantley's Toyota Camry when Curtis pulled the car over early on June 29. Morris killed Curtis and Kocab, a backup officer, then ran away, police say. Brantley drove off.

Morris faces the death penalty if convicted of the killings.

Moody wrote in a seven-page decision that the actions prosecutors cited as evidence to support the misprision of a felony charge against Brantley did not add up to concealment.

Those actions included Brantley's driving away after the shootings, effectively disturbing the crime scene and removing a piece of evidence (her car) and a witness (herself).

"These acts do not demonstrate that Brantley concealed anything having to do with the crime of Morris' possession of a firearm and ammunition," Moody wrote.

There was no evidence, he added, that Brantley altered the car, had it cleaned, tried to hide it or, other than driving away, tried to delay police from finding it.

After the shootings, Morris sent Brantley a text message saying "just lean bak stay loyal," according to authorities. She responded, "Of course. . . . Til death do us part."

But that, Moody concluded, didn't demonstrate an act of concealment about Morris having a gun. The same goes for the fact that the two talked on the phone after the shootings.

"This conversation or conversations do not reflect an act of concealment," Moody wrote. "And an act of concealment must be carried out, not merely talked about."

Finally, prosecutors said Brantley would not tell detectives who the passenger in her car was. She refused to answer the question more than 100 times.

No matter.

"Case law makes it clear that refusing to answer a question from law enforcement or remaining silent cannot constitute an act of concealment," Moody wrote. That's "because of the impact such a ruling would have on the defendant's Fifth Amendment privilege against self-incrimination."

In an e-mail, U.S. Attorney Robert O'Neill said prosecutors were "evaluating the judge's order in order to determine whether an appeal is warranted."

Brantley and her mother, Mischell Brantley, were at home Thursday afternoon when they heard from friends and news reports that the indictment had been dismissed.

"We're very elated," Mischell Brantley said. "It's what should have happened from the beginning. It's not about what they think, they feel. It's about the facts, and they didn't meet the burden of proof for the misprision charge."

That said, Mischell Brantley said she grieves for the slain officers and their families.

"This in no way negates what happened" to them, she said.

Brantley's attorney struck a similar note in a written statement Thursday night.

"On the one hand, a person has been granted relief from a questionable and legally infirm prosecution," defense attorney Grady Irvin Jr. said. "On the other hand, two people were unnecessarily and brutally killed."

Irvin did say the fact that Brantley has not been charged with aiding, abetting or participating in the officers' deaths "clearly demonstrates that she had nothing, whatsoever, to do with the criminal conduct in these matters."

A Tampa police spokeswoman declined to comment on Moody's decision.

Mark Cox, a spokesman for the Hillsborough County State Attorney's Office, said he could not say whether officials would consider a state charge against Brantley.

"It's a pending case and an active investigation, and we're not in a position to comment further than that," Cox said.

Former state prosecutor Mike Benito, now a defense lawyer, said a charge of being an accessory to the crime after the fact might be a possibility.

"I think they could still charge if they believe there's enough there," he said.

But two other ex-prosecutors had their doubts.

"I think if they could have filed something they would have," said lawyer Lyann Goudie. "If there would have been a basis for them to have charged her, they would have charged her."

To be charged as an accessory after the fact, "you have to do something affirmatively" to aid someone who committed a felony, Goudie said.

How about tampering with evidence by removing the car?

"I think it's a stretch to say that that's tampering with evidence," lawyer Eddie Suarez said. "Tampering with evidence is something willful. It requires intent" to undermine or thwart an investigation.

In this case, a defense attorney would likely argue that someone who had just seen a passenger in her car kill two police officers might drive off in fear and panic. The driver might worry about being the only eyewitness to the shootings and the fact that the shooter had a gun.

That, lawyers said, could make it hard to prove that Brantley was trying to help Morris.

Finally, in Florida, it's not a crime to witness a crime and not report it, Suarez said.

Goudie said what happened was horrible, and it's no wonder people are angry at Brantley.

"Everybody's upset with her," she said. "Nobody thinks she did the right thing on this case. But at the end of the day, not doing the right thing doesn't always equal a crime."